I wouldn't just buy a new battery yet as you don't know what's going on.NewsyL wrote: ↑ I do not know how full it was when we first parked the car. The battery is less than 2 years old but the car was problematic when we took possession a few months ago. It has drained dead several times since and I suspect we'll be buying a new battery in order to start it up at least once every couple of weeks.
It is what comes after buying the new battery that I'm worried about.
My advice would be:
1. Disconnect that battery and do some preventative maintenance on it first (ie remove battery, wash battery with some mild soap and water, clean off terminals, check/fill fluid levels if possible, charge battery fully with external charger, and get the battery tested the day after fully charging the battery).
2. Once you get the results of the battery test on a fully charged battery, you'll have a better idea of the next steps.